JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k) (l) under the Securities Exchange Act of 1934, as amended, the undersigned hereby agree to the joint filing of the attached Schedule 13G, and any and all amendments thereto, and expressly authorize Invesco Ltd., as the ultimate parent company of each of its undersigned subsidiaries, to file such Schedule 13G, and any and all amendments thereto, on behalf of each of them.

Dated: 12/31/2014

Invesco Ltd.

By: /s/ Lisa Brinkley

Name: Lisa Brinkley

Title: Global Assurance Officer

Invesco Advisers, Inc.

By: /s/ Todd L. Spillane

Name: Todd L. Spillane

Title: Chief Compliance Officer

Invesco Canada Ltd.

By: /s/ Daniela Nalli

Name: Daniela Nalli

Title: Chief Compliance Officer

Invesco Trust Company

By: /s/ Kevin Lyman

Name: Kevin Lyman

Title: General Counsel

Invesco Hong Kong Limited

By: /s/ Asha Balachandra

Name: Asha Balachandra

Title: Reg. Head of Legal AP

Invesco Asset Management Deutschland GmbH

By: /s/ Stephanie Ehrenfried

Name: Stephanie Ehrenfried

Title: Head of Legal Continental Europe & Cross-Border Funds

Invesco Asset Management Limited

By: /s/ Ross Maclean

Name: Ross Maclean

Title: Director of UK Compliance

Invesco Asset Management S.A.

By: /s/ Matthieu Grosclaude

Name: Matthieu Grosclaude

Title: Deputy-CEO, Invesco Asset Management S.A

Invesco Asset Management S.A.

By: /s/ Bemard Aybran

Name: Bernard Aybran

Title: Deputy-CEO

Invesco Asset Management Osterreich GmbH

By: /s/ Thomas Kraus

Name: Thomas Kraus

Title: Head of Institutional Business D-A-CH

Invesco Management S.A.

By: /s/ Marie-Hélène Boulanger

Name: Marie-Hélène Boulanger

Title: Head of Risk Governance

Invesco Taiwan Limited

By: /s/ Asha Balachandra

Name: Asha Balachandra

Title: Reg. Head of Legal, AP

Invesco Asset Management (Japan) Limited

By: /s/ Asha Balachandra

Name: Asha Balachandra

Title: Reg. Head of Legal, AP

Invesco Asset Management Singapore Limited

By: /s/ ­ Asha Balachandra

Name: Asha Balachandra

Title: Reg. Head of Legal, AP

Invesco Global Asset Management Limited

By: /s/ Cormac O’Sullivan

Name: Cormac O'Sullivan

Title: Head of PMO, EU

Invesco PowerShares Capital Management

By: /s/ Deanna Marotz

Name: Deanna Marotz

Title: Chief Compliance Officer

Invesco Investment Advisers, LLC

By: /s/ Jesse Frazier

Name: Jesse Frazier

Title: Chief Compliance Officer

Invesco Australia Ltd.

By: /s/ Jane Stewart

Name: Jane Stewart

Title: Compliance Manager